Hello Practo User,
10 am to 3 pm is the best time to get yourself exposed to sunlight for the purpose of getting
Vitamin D.
At this time the UV index is highest.
However fog, pollution and climatic conditions need to be kept in mind.
You should protect your face and eyes and expose the body parts as much as possible .
Exposing 20% of body surface for an hour will give you about 2000 IU.
Regards.